Fixes to the state machine to properly support software reset and to fix

PIO writes.  This was mainly related to not shadowing the status register
properly, and also not setting some of the status bits expected by the
operating system for the PIO write protocol.

--HG--
extra : convert_revision : fcdfd588be6e4f237aa6057889f0b3bdf4ea7631

2 files changed, 119 insertions, 73 deletions

diff --git a/dev/ide_disk.cc b/dev/ide_disk.cc
index ddd4a09e7..e8baa7539 100644
--- a/dev/ide_disk.cc
+++ b/dev/ide_disk.cc
@@ -61,25 +61,12 @@ IdeDisk::IdeDisk(const string &name, DiskImage *img, PhysicalMemory *phys,
       dmaWriteWaitEvent(this), dmaPrdReadEvent(this),
       dmaReadEvent(this), dmaWriteEvent(this)
 {
+    // Reset the device state
+    reset(id);
+
     // calculate disk delay in microseconds
     diskDelay = (delay * ticksPerSecond / 100000);
 
-    // initialize the data buffer and shadow registers
-    dataBuffer = new uint8_t[MAX_DMA_SIZE];
-
-    memset(dataBuffer, 0, MAX_DMA_SIZE);
-    memset(&cmdReg, 0, sizeof(CommandReg_t));
-    memset(&curPrd.entry, 0, sizeof(PrdEntry_t));
-
-    dmaInterfaceBytes = 0;
-    curPrdAddr = 0;
-    curSector = 0;
-    curCommand = 0;
-    cmdBytesLeft = 0;
-    drqBytesLeft = 0;
-    dmaRead = false;
-    intrPending = false;
-
     // fill out the drive ID structure
     memset(&driveID, 0, sizeof(struct hd_driveid));
 
@@ -132,6 +119,32 @@ IdeDisk::IdeDisk(const string &name, DiskImage *img, PhysicalMemory *phys,
     driveID.dma_ultra = 0x10;
     // Statically set hardware config word
     driveID.hw_config = 0x4001;
+}
+
+IdeDisk::~IdeDisk()
+{
+    // destroy the data buffer
+    delete [] dataBuffer;
+}
+
+void
+IdeDisk::reset(int id)
+{
+    // initialize the data buffer and shadow registers
+    dataBuffer = new uint8_t[MAX_DMA_SIZE];
+
+    memset(dataBuffer, 0, MAX_DMA_SIZE);
+    memset(&cmdReg, 0, sizeof(CommandReg_t));
+    memset(&curPrd.entry, 0, sizeof(PrdEntry_t));
+
+    dmaInterfaceBytes = 0;
+    curPrdAddr = 0;
+    curSector = 0;
+    cmdBytes = 0;
+    cmdBytesLeft = 0;
+    drqBytesLeft = 0;
+    dmaRead = false;
+    intrPending = false;
 
     // set the device state to idle
     dmaState = Dma_Idle;
@@ -147,13 +160,7 @@ IdeDisk::IdeDisk(const string &name, DiskImage *img, PhysicalMemory *phys,
     }
 
     // set the device ready bit
-    cmdReg.status |= STATUS_DRDY_BIT;
-}
-
-IdeDisk::~IdeDisk()
-{
-    // destroy the data buffer
-    delete [] dataBuffer;
+    status = STATUS_DRDY_BIT;
 }
 
 ////
@@ -216,6 +223,7 @@ IdeDisk::read(const Addr &offset, bool byte, bool cmdBlk, uint8_t *data)
         // determine if an action needs to be taken on the state machine
         if (offset == STATUS_OFFSET) {
             action = ACT_STAT_READ;
+            *data = status; // status is in a shadow, explicity copy
         } else if (offset == DATA_OFFSET) {
             if (byte)
                 action = ACT_DATA_READ_BYTE;
@@ -230,7 +238,7 @@ IdeDisk::read(const Addr &offset, bool byte, bool cmdBlk, uint8_t *data)
         if (!byte)
             panic("Invalid 16-bit read from control block\n");
 
-        *data = ((uint8_t *)&cmdReg)[STATUS_OFFSET];
+        *data = status;
     }
 
     if (action != ACT_NONE)
@@ -262,6 +270,8 @@ IdeDisk::write(const Addr &offset, bool byte, bool cmdBlk, const uint8_t *data)
                 action = ACT_DATA_WRITE_BYTE;
             else
                 action = ACT_DATA_WRITE_SHORT;
+        } else if (offset == SELECT_OFFSET) {
+            action = ACT_SELECT_WRITE;
         }
 
     } else {
@@ -271,8 +281,13 @@ IdeDisk::write(const Addr &offset, bool byte, bool cmdBlk, const uint8_t *data)
         if (!byte)
             panic("Invalid 16-bit write to control block\n");
 
-        if (*data & CONTROL_RST_BIT)
-            panic("Software reset not supported!\n");
+        if (*data & CONTROL_RST_BIT) {
+            // force the device into the reset state
+            devState = Device_Srst;
+            action = ACT_SRST_SET;
+        } else if (devState == Device_Srst && !(*data & CONTROL_RST_BIT)) {
+            action = ACT_SRST_CLEAR;
+        }
 
         nIENBit = (*data & CONTROL_IEN_BIT) ? true : false;
     }
@@ -625,9 +640,6 @@ IdeDisk::startCommand()
     uint32_t size = 0;
     dmaRead = false;
 
-    // copy the command to the shadow
-    curCommand = cmdReg.command;
-
     // Decode commands
     switch (cmdReg.command) {
         // Supported non-data commands
@@ -656,7 +668,7 @@ IdeDisk::startCommand()
 
         // Supported PIO data-in commands
       case WIN_IDENTIFY:
-        cmdBytesLeft = sizeof(struct hd_driveid);
+        cmdBytes = cmdBytesLeft = sizeof(struct hd_driveid);
         devState = Prepare_Data_In;
         action = ACT_DATA_READY;
         break;
@@ -667,9 +679,9 @@ IdeDisk::startCommand()
             panic("Attempt to perform CHS access, only supports LBA\n");
 
         if (cmdReg.sec_count == 0)
-            cmdBytesLeft = (256 * SectorSize);
+            cmdBytes = cmdBytesLeft = (256 * SectorSize);
         else
-            cmdBytesLeft = (cmdReg.sec_count * SectorSize);
+            cmdBytes = cmdBytesLeft = (cmdReg.sec_count * SectorSize);
 
         curSector = getLBABase();
 
@@ -685,9 +697,9 @@ IdeDisk::startCommand()
             panic("Attempt to perform CHS access, only supports LBA\n");
 
         if (cmdReg.sec_count == 0)
-            cmdBytesLeft = (256 * SectorSize);
+            cmdBytes = cmdBytesLeft = (256 * SectorSize);
         else
-            cmdBytesLeft = (cmdReg.sec_count * SectorSize);
+            cmdBytes = cmdBytesLeft = (cmdReg.sec_count * SectorSize);
 
         curSector = getLBABase();
 
@@ -703,9 +715,9 @@ IdeDisk::startCommand()
             panic("Attempt to perform CHS access, only supports LBA\n");
 
         if (cmdReg.sec_count == 0)
-            cmdBytesLeft = (256 * SectorSize);
+            cmdBytes = cmdBytesLeft = (256 * SectorSize);
         else
-            cmdBytesLeft = (cmdReg.sec_count * SectorSize);
+            cmdBytes = cmdBytesLeft = (cmdReg.sec_count * SectorSize);
 
         curSector = getLBABase();
 
@@ -719,9 +731,11 @@ IdeDisk::startCommand()
 
     if (action != ACT_NONE) {
         // set the BSY bit
-        cmdReg.status |= STATUS_BSY_BIT;
+        status |= STATUS_BSY_BIT;
         // clear the DRQ bit
-        cmdReg.status &= ~STATUS_DRQ_BIT;
+        status &= ~STATUS_DRQ_BIT;
+        // clear the DF bit
+        status &= ~STATUS_DF_BIT;
 
         updateState(action);
     }
@@ -765,16 +779,30 @@ void
 IdeDisk::updateState(DevAction_t action)
 {
     switch (devState) {
+      case Device_Srst:
+        if (action == ACT_SRST_SET) {
+            // set the BSY bit
+            status |= STATUS_BSY_BIT;
+        } else if (action == ACT_SRST_CLEAR) {
+            // clear the BSY bit
+            status &= ~STATUS_BSY_BIT;
+
+            // reset the device state
+            reset(devID);
+        }
+        break;
+
       case Device_Idle_S:
-        if (!isDEVSelect())
+        if (action == ACT_SELECT_WRITE && !isDEVSelect()) {
             devState = Device_Idle_NS;
-        else if (action == ACT_CMD_WRITE)
+        } else if (action == ACT_CMD_WRITE) {
             startCommand();
+        }
 
         break;
 
       case Device_Idle_SI:
-        if (!isDEVSelect()) {
+        if (action == ACT_SELECT_WRITE && !isDEVSelect()) {
             devState = Device_Idle_NS;
             intrClear();
         } else if (action == ACT_STAT_READ || isIENSet()) {
@@ -788,7 +816,7 @@ IdeDisk::updateState(DevAction_t action)
         break;
 
       case Device_Idle_NS:
-        if (isDEVSelect()) {
+        if (action == ACT_SELECT_WRITE && isDEVSelect()) {
             if (!isIENSet() && intrPending) {
                 devState = Device_Idle_SI;
                 intrPost();
@@ -826,12 +854,12 @@ IdeDisk::updateState(DevAction_t action)
             }
         } else if (action == ACT_DATA_READY) {
             // clear the BSY bit
-            cmdReg.status &= ~STATUS_BSY_BIT;
+            status &= ~STATUS_BSY_BIT;
             // set the DRQ bit
-            cmdReg.status |= STATUS_DRQ_BIT;
+            status |= STATUS_DRQ_BIT;
 
             // copy the data into the data buffer
-            if (curCommand == WIN_IDENTIFY) {
+            if (cmdReg.command == WIN_IDENTIFY) {
                 // Reset the drqBytes for this block
                 drqBytesLeft = sizeof(struct hd_driveid);
 
@@ -887,9 +915,9 @@ IdeDisk::updateState(DevAction_t action)
                 } else {
                     devState = Prepare_Data_In;
                     // set the BSY_BIT
-                    cmdReg.status |= STATUS_BSY_BIT;
+                    status |= STATUS_BSY_BIT;
                     // clear the DRQ_BIT
-                    cmdReg.status &= ~STATUS_DRQ_BIT;
+                    status &= ~STATUS_DRQ_BIT;
 
                     /** @todo change this to a scheduled event to simulate
                         disk delay */
@@ -910,20 +938,23 @@ IdeDisk::updateState(DevAction_t action)
             } else {
                 devState = Device_Idle_S;
             }
-        } else if (cmdBytesLeft != 0) {
+        } else if (action == ACT_DATA_READY && cmdBytesLeft != 0) {
             // clear the BSY bit
-            cmdReg.status &= ~STATUS_BSY_BIT;
+            status &= ~STATUS_BSY_BIT;
             // set the DRQ bit
-            cmdReg.status |= STATUS_DRQ_BIT;
+            status |= STATUS_DRQ_BIT;
 
             // clear the data buffer to get it ready for writes
             memset(dataBuffer, 0, MAX_DMA_SIZE);
 
-            if (!isIENSet()) {
+            // reset the drqBytes for this block
+            drqBytesLeft = SectorSize;
+
+            if (cmdBytesLeft == cmdBytes || isIENSet()) {
+                devState = Transfer_Data_Out;
+            } else {
                 devState = Data_Ready_INTRQ_Out;
                 intrPost();
-            } else {
-                devState = Transfer_Data_Out;
             }
         }
         break;
@@ -956,9 +987,11 @@ IdeDisk::updateState(DevAction_t action)
                 writeDisk(curSector++, dataBuffer);
 
                 // set the BSY bit
-                cmdReg.status |= STATUS_BSY_BIT;
+                status |= STATUS_BSY_BIT;
+                // set the seek bit
+                status |= STATUS_SEEK_BIT;
                 // clear the DRQ bit
-                cmdReg.status &= ~STATUS_DRQ_BIT;
+                status &= ~STATUS_DRQ_BIT;
 
                 devState = Prepare_Data_Out;
 
@@ -982,9 +1015,9 @@ IdeDisk::updateState(DevAction_t action)
             }
         } else if (action == ACT_DMA_READY) {
             // clear the BSY bit
-            cmdReg.status &= ~STATUS_BSY_BIT;
+            status &= ~STATUS_BSY_BIT;
             // set the DRQ bit
-            cmdReg.status |= STATUS_DRQ_BIT;
+            status |= STATUS_DRQ_BIT;
 
             devState = Transfer_Data_Dma;
 
@@ -1001,7 +1034,7 @@ IdeDisk::updateState(DevAction_t action)
             // clear the BSY bit
             setComplete();
             // set the seek bit
-            cmdReg.status |= 0x10;
+            status |= STATUS_SEEK_BIT;
             // clear the controller state for DMA transfer
             ctrl->setDmaComplete(this);
 
@@ -1058,7 +1091,7 @@ IdeDisk::serialize(ostream &os)
     SERIALIZE_SCALAR(cmdReg.cyl_low);
     SERIALIZE_SCALAR(cmdReg.cyl_high);
     SERIALIZE_SCALAR(cmdReg.drive);
-    SERIALIZE_SCALAR(cmdReg.status);
+    SERIALIZE_SCALAR(status);
     SERIALIZE_SCALAR(nIENBit);
     SERIALIZE_SCALAR(devID);
 
@@ -1070,9 +1103,9 @@ IdeDisk::serialize(ostream &os)
 
     // Serialize current transfer related information
     SERIALIZE_SCALAR(cmdBytesLeft);
+    SERIALIZE_SCALAR(cmdBytes);
     SERIALIZE_SCALAR(drqBytesLeft);
     SERIALIZE_SCALAR(curSector);
-    SERIALIZE_SCALAR(curCommand);
     SERIALIZE_SCALAR(dmaRead);
     SERIALIZE_SCALAR(dmaInterfaceBytes);
     SERIALIZE_SCALAR(intrPending);
@@ -1110,7 +1143,7 @@ IdeDisk::unserialize(Checkpoint *cp, const string &section)
     UNSERIALIZE_SCALAR(cmdReg.cyl_low);
     UNSERIALIZE_SCALAR(cmdReg.cyl_high);
     UNSERIALIZE_SCALAR(cmdReg.drive);
-    UNSERIALIZE_SCALAR(cmdReg.status);
+    UNSERIALIZE_SCALAR(status);
     UNSERIALIZE_SCALAR(nIENBit);
     UNSERIALIZE_SCALAR(devID);
 
@@ -1121,10 +1154,10 @@ IdeDisk::unserialize(Checkpoint *cp, const string &section)
     UNSERIALIZE_SCALAR(curPrdAddr);
 
     // Unserialize current transfer related information
+    UNSERIALIZE_SCALAR(cmdBytes);
     UNSERIALIZE_SCALAR(cmdBytesLeft);
     UNSERIALIZE_SCALAR(drqBytesLeft);
     UNSERIALIZE_SCALAR(curSector);
-    UNSERIALIZE_SCALAR(curCommand);
     UNSERIALIZE_SCALAR(dmaRead);
     UNSERIALIZE_SCALAR(dmaInterfaceBytes);
     UNSERIALIZE_SCALAR(intrPending);
diff --git a/dev/ide_disk.hh b/dev/ide_disk.hh
index 35e7404d5..eb8c8a047 100644
--- a/dev/ide_disk.hh
+++ b/dev/ide_disk.hh
@@ -94,6 +94,8 @@ class PrdTableEntry {
 #define STATUS_BSY_BIT  0x80
 #define STATUS_DRDY_BIT 0x40
 #define STATUS_DRQ_BIT  0x08
+#define STATUS_SEEK_BIT 0x10
+#define STATUS_DF_BIT   0x20
 #define DRIVE_LBA_BIT   0x40
 
 #define DEV0 (0)
@@ -114,10 +116,7 @@ typedef struct CommandReg {
         uint8_t drive;
         uint8_t head;
     };
-    union {
-        uint8_t status;
-        uint8_t command;
-    };
+    uint8_t command;
 } CommandReg_t;
 
 typedef enum Events {
@@ -135,6 +134,7 @@ typedef enum DevAction {
     ACT_CMD_WRITE,
     ACT_CMD_COMPLETE,
     ACT_CMD_ERROR,
+    ACT_SELECT_WRITE,
     ACT_STAT_READ,
     ACT_DATA_READY,
     ACT_DATA_READ_BYTE,
@@ -142,7 +142,9 @@ typedef enum DevAction {
     ACT_DATA_WRITE_BYTE,
     ACT_DATA_WRITE_SHORT,
     ACT_DMA_READY,
-    ACT_DMA_DONE
+    ACT_DMA_DONE,
+    ACT_SRST_SET,
+    ACT_SRST_CLEAR
 } DevAction_t;
 
 typedef enum DevState {
@@ -151,6 +153,9 @@ typedef enum DevState {
     Device_Idle_SI,
     Device_Idle_NS,
 
+    // Software reset
+    Device_Srst,
+
     // Non-data commands
     Command_Execution,
 
@@ -202,6 +207,8 @@ class IdeDisk : public SimObject
     struct hd_driveid driveID;
     /** Data buffer for transfers */
     uint8_t *dataBuffer;
+    /** Number of bytes in command data transfer */
+    uint32_t cmdBytes;
     /** Number of bytes left in command data transfer */
     uint32_t cmdBytesLeft;
     /** Number of bytes left in DRQ block */
@@ -210,8 +217,8 @@ class IdeDisk : public SimObject
     uint32_t curSector;
     /** Command block registers */
     CommandReg_t cmdReg;
-    /** Shadow of the current command code */
-    uint8_t curCommand;
+    /** Status register */
+    uint8_t status;
     /** Interrupt enable bit */
     bool nIENBit;
     /** Device state */
@@ -249,6 +256,11 @@ class IdeDisk : public SimObject
     ~IdeDisk();
 
     /**
+     * Reset the device state
+     */
+    void reset(int id);
+
+    /**
      * Set the controller for this device
      * @param c The IDE controller
      */
@@ -306,17 +318,18 @@ class IdeDisk : public SimObject
     void updateState(DevAction_t action);
 
     // Utility functions
-    bool isBSYSet() { return (cmdReg.status & STATUS_BSY_BIT); }
+    bool isBSYSet() { return (status & STATUS_BSY_BIT); }
     bool isIENSet() { return nIENBit; }
     bool isDEVSelect() { return ((cmdReg.drive & SELECT_DEV_BIT) == devID); }
 
     void setComplete()
     {
         // clear out the status byte
-        cmdReg.status = 0;
-
+        status = 0;
         // set the DRDY bit
-        cmdReg.status |= STATUS_DRDY_BIT;
+        status |= STATUS_DRDY_BIT;
+        // set the SEEK bit
+        status |= STATUS_SEEK_BIT;
     }
 
     uint32_t getLBABase()